From: fche@redhat.com (Frank Ch. Eigler)
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
"H. Peter Anvin" <hpa@zytor.com>,
fche@redhat.com
Subject: Re: [PATCH 6/9][RFC] kprobes: Allow probe on ftrace reserved text (but move it)
Date: Wed, 02 May 2012 16:40:15 -0400 [thread overview]
Message-ID: <y0mhavyl3kg.fsf@fche.csb> (raw)
In-Reply-To: <20120502193237.321234712@goodmis.org> (Steven Rostedt's message of "Wed, 02 May 2012 15:24:24 -0400")
rostedt wrote:
> [...] Added KPROBE_FLAG_MOVED (as suggested by Masami) that is set
> when the address is moved to get around an ftrace nop. [...]
Steve, perhaps my earlier comments on this got lost during the mailing
list outage.
The gist is that a KPROBE_FLAG_MOVED being set this way accomplishes
very little since nothing is looking for that flag. Instead, you
should patch {arch/*}/kernel/kprobe.c kprobe_handler() to subtract
MCOUNT_INSN_SIZE back out from pt_regs->ip if KPROBE_FLAG_MOVED was
set. That way, kprobes clients need do not perceive the int3 movement.
- FChE
next prev parent reply other threads:[~2012-05-02 20:40 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-02 19:24 [PATCH 0/9][RFC] ftrace: ftrace location lookup speedup, and clean ups Steven Rostedt
2012-05-02 19:24 ` [PATCH 1/9][RFC] ftrace: Sort all function addresses, not just per page Steven Rostedt
2012-05-02 19:24 ` [PATCH 2/9][RFC] ftrace: Remove extra helper functions Steven Rostedt
2012-05-02 19:24 ` [PATCH 3/9][RFC] ftrace: Speed up search by skipping pages by address Steven Rostedt
2012-05-02 19:24 ` [PATCH 4/9][RFC] ftrace: Consolidate ftrace_location() and ftrace_text_reserved() Steven Rostedt
2012-05-02 19:24 ` [PATCH 5/9][RFC] ftrace: Return record ip addr for ftrace_location() Steven Rostedt
2012-05-02 19:24 ` [PATCH 6/9][RFC] kprobes: Allow probe on ftrace reserved text (but move it) Steven Rostedt
2012-05-02 20:40 ` Frank Ch. Eigler [this message]
2012-05-02 23:40 ` Steven Rostedt
2012-05-07 11:37 ` Masami Hiramatsu
2012-05-07 11:59 ` Masami Hiramatsu
2012-05-07 12:44 ` Steven Rostedt
2012-05-07 12:51 ` Steven Rostedt
2012-05-07 12:43 ` Steven Rostedt
2012-05-08 3:08 ` Masami Hiramatsu
2012-05-08 13:04 ` Steven Rostedt
2012-05-09 5:53 ` Masami Hiramatsu
2012-05-09 8:12 ` Masami Hiramatsu
2012-05-09 9:02 ` Masami Hiramatsu
2012-05-09 14:50 ` Steven Rostedt
2012-05-10 11:54 ` [RFC PATCH -tip ] x86/kprobes: kprobes call optimization Masami Hiramatsu
2012-05-11 8:29 ` Masami Hiramatsu
2012-05-02 19:24 ` [PATCH 7/9][RFC] ftrace: Make ftrace_modify_all_code() global for archs to use Steven Rostedt
2012-05-02 19:24 ` [PATCH 8/9][RFC] ftrace/x86: Have x86 ftrace use the ftrace_modify_all_code() Steven Rostedt
2012-05-02 19:24 ` [PATCH 9/9][RFC] ftrace: Remove selecting FRAME_POINTER with FUNCTION_TRACER Steven Rostedt
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